1. Field of the Invention
The present invention relates to an etching method and an etching apparatus.
2. Description of the Related Art
As disclosed in Japanese Laid-Open Patent Application Publication No. 7-22393, a method of forming a hole with a high aspect ratio by etching a silicon oxide film is proposed. For example, Japanese Laid-Open Patent Application Publication No. 7-22393 discloses a dry etching method for forming an opening with a high aspect ratio and preventing the film from depositing on an inner wall of a chamber to reduce a period of time required for a cleaning process of an etching apparatus.
Moreover, as an example of the method of forming the hole with the high aspect ratio in the silicon oxide film by etching, a technique is proposed of forming the hole by etching the film while using C4F8/C4F6/Ar/O2 containing gas and keeping a temperature of a wafer high so as to deposit a reaction product on the opening of the hole as little as possible.
However, in the etching to form a hole or a trench with a high aspect ratio, depth loading, which is a phenomenon in which the etching does not progress at the bottom of the hole or the trench, occurs as the etching progresses. The depth loading is likely to occur as the aspect ratio becomes high.